Progress in the treatment of gastric cancer in Japan over the last 50 years

Predicting chemotherapy responsiveness in gastric cancer through machine learning analysis of genome, immune, and neutrophil signatures

BACKGROUND

Gastric cancer is a major oncological challenge, ranking highly among causes of cancer-related mortality worldwide. This study was initiated to address the variability in patient responses to combination chemotherapy, highlighting the need for personalized treatment strategies based on genomic data.

METHODS

We analyzed whole-genome and RNA sequences from biopsy specimens of 65 advanced gastric cancer patients before their chemotherapy treatment. Using machine learning techniques, we developed a model with 123 omics features, such as immune signatures and copy number variations, to predict their chemotherapy outcomes.

RESULTS

The model demonstrated a prediction accuracy of 70-80% in forecasting chemotherapy responses in both test and validation cohorts. Notably, tumor-associated neutrophils emerged as significant predictors of treatment efficacy. Further single-cell analyses from cancer tissues revealed different neutrophil subgroups with potential antitumor activities suggesting their usefulness as biomarkers for treatment decisions.

CONCLUSIONS

This study confirms the utility of machine learning in advancing personalized medicine for gastric cancer by identifying tumor-associated neutrophils and their subgroups as key indicators of chemotherapy response. These findings could lead to more tailored and effective treatment plans for patients.

Lymph Node Metastasis and Its Risk Factors for Early Gastritis Individuals Who Underwent Noncurative Endoscopic Resection: A Systematic Review and Meta-Analysis

Background

In the present review, we carried out a systematic review and meta-analysis to analyze possible lymph node metastasis (LNM) hazards in individuals with endoscopic resection of gastric cancer.

Methods

Relevant literature was selected by evaluating the PubMed, Cochrane Library, and Google Scholar electronic databases since from inception to March 2022. Corresponding clinicopathological outcomes were summarized, and pooled log odds ratios and 95% confidence intervals were assessed. The random effect model was preferred if variations among studies is high otherwise fixed effect model was preferred.

Results

Overall, 12 associated papers, including 4808 early gastric cancer individuals who endured more surgery after noncurative endoscopic resection, were entered into this analysis. The outcomes showed that submucosal invasion (log odd ratio 1.75, 95% (CI): 0.77-3.95, I2 = 80.0%); vertical margin (log odd ratio 6.53, 95% (CI): 2.81-15.17, I2 = 65%); horizontal margin (log Odd ratio 0.69 95% (CI): 0.22-2.14, I2 = 52%), lymphatic invasion (Odd ratio 6.33 95% (CI): 1.98-20.24, I2 = 91%), and vascular invasion (Odd ratio 3.55, 95% (CI): 1.31-9.58, I2 = 92%) was significantly related to metastasis of lymph node for these patients.

Conclusion

There was a significant association of LNM hazards in individuals with endoscopic resection of gastric cancer. Therefore, invasion to lymph, vascular, submucosa and positive vertical margin should be strongly noticed when selecting surgical treatment factors.

Prognostic Impact of Tumor Growth Rate During Second-line Chemotherapy in Patients With Gastric Cancer

Background/Aim

Despite the remarkable developments in chemotherapy for gastric cancer (GC), rapid tumor growth is sometimes experienced during chemotherapy. This study investigated the association of tumor growth rate (TGR) during second-line chemotherapy with the prognosis of patients with GC.

Patients and Methods

We retrospectively reviewed 29 patients with GC treated with nab-paclitaxel plus ramucirumab as second-line chemotherapy between 2017 and 2019 at Osaka Metropolitan University. Of them, 13 cases with target lesions were classified into two groups according to TGR using a cutoff value of 0.25. Clinicopathological factors and survival outcomes were compared between the high TGR (n=5) and low TGR (n=8) groups.

Results

The median duration of first-line chemotherapy was significantly longer in the high TGR group than in the low TGR group [median 298 days vs. 72.5 days, p=0.030]. Progressive disease (PD) was observed in 60% of patients with high TGR, whereas stable disease (SD) was observed in 75% patients with low TGR. The median survival time (MST) after starting chemotherapy was 488 days in the low TGR group but was not reached in the high TGR group (log rank p=0.215). The MST after PD was 145 days in the low TGR group but was not estimated in the high TGR group (log rank p=0.345).

Conclusion

Based on the absence of significant differences in survival outcomes between the high and low TGR groups, sequential late-line chemotherapy might be considered important, even for patients with high TGR.

Robotic gastrectomy is more beneficial for advanced than early-stage gastric cancer: a comparison with laparoscopic gastrectomy using propensity score matching

BACKGROUND

Gastric cancer is the fifth most prevalent malignancy globally and the fourth major contributor to cancer-related mortality. The comparative effectiveness of robotic gastrectomy (RG) versus laparoscopic gastrectomy (LG) at different stages of gastric cancer is unclear regarding surgical and survival outcomes. We compared surgical and survival outcomes between RG and LG in early-stage (cStage I) and advanced (cStage II/III) gastric cancers to elucidate the difference in the efficacy of RG across various stages of gastric cancer.

METHODS

We identified 299 patients (LG, 170; RG, 129) with cStage II/III disease and 569 (LG, 455; RG, 114) with cStage I disease who underwent either LG or RG. Following propensity score matching for RG and LG, 118 pairs were selected for cStage II/II and 113 pairs for cStage I. Surgical and survival outcomes of LG and RG were separately compared for cStage II/III and cStage I.

RESULTS

In cStage II/III, RG showed significantly fewer intra-abdominal complications of Clavien-Dindo (C.D.) Grade ≥ III in the RG group than in the LG group (LG = 8.5 vs. RG = 1.7%, P = 0.033). Multivariate analysis identified LG as an independent risk factor for intra-abdominal complications of C.D. Grade ≥ III (OR 5.69, 95% CI 1.17-27.70, P = 0.031). However, in cStage I, no difference in surgical outcomes between LG and RG was observed. No differences were observed in survival outcomes between LG and RG in both cStage I or cStage II/III.

CONCLUSIONS

The real benefit of RG was demonstrated in surgical outcomes, especially for advanced-stage gastric cancer.

Standardized procedure for preventing late intestinal complications following minimally invasive total gastrectomy for gastric cancer: a single-center retrospective cohort study

BACKGROUND

Although minimally invasive total gastrectomy for gastric cancer is commonly performed, reports regarding late complications are limited. We have made several improvements each time we experienced severe late complications since 2009. This study aimed to evaluate the clinical efficacy of these improved procedures in preventing late complications.

METHODS

Between January 2009 and December 2019, 302 patients who underwent laparoscopic or robotic total gastrectomy for gastric cancer were enrolled. The patients were divided into two groups: Period-I (2009-2013, before established standardization of procedure, 166 patients) and Period-II (2014-2019, after established standardization of procedure, 136 patients). The standardized procedure comprised four major steps, including closure of the mesentery defects and diaphragm crus, circumferential fixation of the anastomotic site into the diaphragm, and linearization around the anastomotic site of esophagojejunostomy. The incidence of late complications was retrospectively compared between the two groups.

RESULTS

Late overall complications that occurred over 30 days after surgery were observed in 19 (6.3%) patients. In all, 14 of 24 (58.3%) patients admitted due to late intestinal complications eventually required reoperation for treatment. The most frequent complication was nonstenotic outlet obstruction of the distal jejunal limb. The incidence of late overall complications was significantly lower in Period-II than in Period-I (2.9 vs 9.0%, p = 0.030). Intestinal complications were reduced considerably in Period-II. The 3-year cumulative incidence rate of late overall complications was significantly lower in Period-II than in Period-I (0.03 vs 0.10, p = 0.035). Period-I as the only independent risk factor for the development of late intestinal complications.

CONCLUSION

Late complications after laparoscopic total gastrectomy sometimes occurred, and more than half of the patients with intestinal complications required reoperation. Our standardized procedure was associated with a lower risk of late intestinal complications after minimally invasive total gastrectomy followed by intracorporeal esophagojejunostomy using linear staplers in a cohort of patients with gastric cancer.

Impact of a board certification system and adherence to the clinical practice guidelines for gastric cancer on risk-adjusted surgical mortality after distal and total gastrectomy in Japan: a questionnaire survey of departments registered in the National Clinical Database

PURPOSE

The relationship between board certification, clinical guideline implementation, and quality of gastric cancer surgery remains unclear.

METHODS

A web-based questionnaire survey was administered to departments registered in the National Clinical Database (NCD) of Japan between October 2014 and January 2015. Quality indicators (QIs) based on the Donabedian model were evaluated. Structural QIs (e.g., affiliations with academic societies and board certifications) and process QIs (adherence to clinical practice guidelines for gastric cancer) were assessed using risk-adjusted odds ratios (AORs) for surgical mortality. Multivariable logistic regression models with a generalized estimating equation were used.

RESULTS

A total of 835 departments performing 40,992 distal gastrectomies and 806 departments performing 19,618 total gastrectomies responded. Some certified institutions and physicians showed significant associations, with lower AORs for surgical mortality. Important process QIs included pre- and postoperative abdominal CT scanning, endoscopic resection based on progression, curative resection with D2 dissection for advanced gastric cancer, laparoscopic surgery, and HER2 testing for patients with unresectable recurrent gastric cancer.

CONCLUSIONS

Multiple structural and process QIs are associated with surgical mortality after gastrectomy in Japan. Measuring and visualizing QIs may enhance healthcare improvements.

Role of Recurrence Pattern Multiplicity in Predicting Post-recurrence Survival in Patients Who Underwent Curative Gastrectomy for Gastric Cancer

PURPOSE

This study aimed to investigate the recurrence patterns in patients who underwent curative surgery for gastric cancer (GC) and analyze their prognostic value for post-recurrence survival (PRS).

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 204 patients who experienced GC recurrence following curative gastrectomy for GC at a single institution between January 2012 and December 2017. Specific recurrence patterns (lymph node, peritoneal, and hematogenous) and their multiplicity were analyzed as prognostic factors of PRS.

RESULTS

The median PRS of the 204 patients was 8.3 months (interquartile range [IQR]: 3.2-17.4). For patients with a single recurrence pattern (n=164), the difference in each recurrence pattern did not show a significant prognostic value for PRS (lymph node vs. peritoneal, P=0.343; peritoneal vs. hematogenous, P=0.660; lymph node vs. hematogenous, P=0.822). However, the patients with a single recurrence pattern had significantly longer PRS than those with multiple recurrence patterns (median PRS: 10.2 months [IQR: 3.7-18.7] vs. 3.9 months [IQR: 1.8-10.4]; P=0.037). In the multivariate analysis, multiple recurrence patterns emerged as independent prognostic factors for poor PRS (hazard ratio, 1.553; 95% confidence interval, 1.092-2.208; P=0.014) along with serosal invasion, recurrence within 1 year after gastrectomy, and the absence of post-recurrence chemotherapy.

CONCLUSIONS

Regardless of the specific recurrence pattern, multiple recurrence patterns emerged as independent prognostic factors for poor PRS compared with a single recurrence pattern.

Tyrosine phosphatase SHP2 aggravates tumor progression and glycolysis by dephosphorylating PKM2 in gastric cancer

Gastric cancer (GC) is among the most lethal human malignancies, yet it remains hampered by challenges in fronter of molecular-guided targeted therapy to direct clinical treatment strategies. The protein tyrosine phosphatase Src homology 2 domain-containing phosphatase 2 (SHP2) is involved in the malignant progression of GC. However, the detailed mechanisms of the posttranslational modifications of SHP2 remain poorly understood. Herein, we demonstrated that an allosteric SHP2 inhibitor, SHP099, was able to block tumor proliferation and migration of GC by dephosphorylating the pyruvate kinase M2 type (PKM2) protein. Mechanistically, we found that PKM2 is a bona fide target of SHP2. The dephosphorylation and activation of PKM2 by SHP2 are necessary to exacerbate tumor progression and GC glycolysis. Moreover, we demonstrated a strong correlation between the phosphorylation level of PKM2 and adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) in GC cells. Notably, the low phosphorylation expression of AMPK was negatively correlated with activated SHP2. Besides, we proved that cisplatin could activate SHP2 and SHP099 increased sensitivity to cisplatin in GC. Taken together, our results provide evidence that the SHP2/PKM2/AMPK axis exerts a key role in GC progression and glycolysis and could be a viable therapeutic approach for the therapy of GC.

Delay in diagnosis to treatment and impact on survival of gastric adenocarcinoma in a low income setting without screening facility

The treatment modality of gastric adenocarcinoma (GCA) depends on the stage of the disease at the clinical presentation. Long delays are probably an unfavorable factor for the patient's prognosis. A prospective longitudinal, study involving 145 consecutive GCA was conducted at the National Hospital of Sri Lanka (NHSL). The overall delay (in weeks) was recorded for each patient and divided into four periods-patient, endoscopy, pathology and treatment. The median and Interquartile Range (IQR) duration of delays were calculated and differences were explored with chi square test and Mann Whitney U test Survival analysis was done with Kaplan Meier technique and Cox regression. The median duration of delays for patient, endoscopy, histology reporting delay, other histology delay (specimen transfer delay and report receipt delay) and treatment were 18 (IQR 14-27), 2 (IQR 2-3), 3 (IQR 2-3), 2 (IQR 1-2) and 6 (IQR 4-8) weeks respectively. Delayed patient presentation to hospital was associated with significant adverse median survival 16 (IQR 11.5-22.5) weeks versus 20 (IQR 16-27.5) weeks, p = 0.004. Delay in initiating treatment was associated with significantly lower median survival 04 (IQR 4-6) weeks versus 06 (IQR 4-8) weeks, p = 0.003. Over 60% of both proximal and distal GCA presented at an advanced radiological stage (stage III/IV). The Kaplan Meier analysis showed that the higher hazard function was associated with a higher tumour stage and undergoing chemotherapy. Age of the patient and the treatment modality were significant predictors of the survival. Patient delay and delay in initiation of definitive treatment are the most important factors that adversely affect the outcomes of GCA. Public health interventions aiming to shorten the patient delay time with proper referral for specialist care would play an important role. Also, it is important to minimize these preventable delays and there should be time limits in producing the histopathology report and to establish online portals of hospital and laboratory information systems for easy access of histology reports in future.

Bacterial lipopolysaccharide related genes signature as potential biomarker for prognosis and immune treatment in gastric cancer

The composition of microbial microenvironment is an important factor affecting the development of tumor diseases. However, due to the limitations of current technological levels, we are still unable to fully study and elucidate the depth and breadth of the impact of microorganisms on tumors, especially whether microorganisms have an impact on cancer. Therefore, the purpose of this study is to conduct in-depth research on the role and mechanism of prostate microbiome in gastric cancer (GC) based on the related genes of bacterial lipopolysaccharide (LPS) by using bioinformatics methods. Through comparison in the Toxin Genomics Database (CTD), we can find and screen out the bacterial LPS related genes. In the study, Venn plots and lasso analysis were used to obtain differentially expressed LPS related hub genes (LRHG). Afterwards, in order to establish a prognostic risk score model and column chart in LRHG features, we used univariate and multivariate Cox regression analysis for modeling and composition. In addition, we also conducted in-depth research on the clinical role of immunotherapy with TMB, MSI, KRAS mutants, and TIDE scores. We screened 9 LRHGs in the database. We constructed a prognostic risk score and column chart based on LRHG, indicating that low risk scores have a protective effect on patients. We particularly found that low risk scores are beneficial for immunotherapy through TIDE score evaluation. Based on LPS related hub genes, we established a LRHG signature, which can help predict immunotherapy and prognosis for GC patients. Bacterial lipopolysaccharide related genes can also be biomarkers to predict progression free survival in GC patients.

CircRNA circSLIT2 is a novel diagnostic and prognostic biomarker for gastric cancer

BACKGROUND

Many diseases can mimic the symptoms of gastric cancer (GC). Therefore, misdiagnosis of GC is common. Our preliminary sequencing analysis revealed the altered expression of circSLIT2 in GC. In this study, we further explored the role of circSLIT2 in GC.

METHODS

The research subjects included GC patients, patients with irritable bowel syndrome (IBS), patients with gastric ulcer (GU), patients with gastric tuberculosis (GT), patients with Crohn's disease (CD), and healthy controls (HC). Accumulation of circSLIT2 RNA in both tissue and plasma samples was determined with RT-qPCR. The diagnostic and prognostic values of circSLIT2 for GC were explored by performing ROC and survival curve analysis. The χ2-test was applied for association analysis.

RESULTS

Increased circSLIT2 RNA accumulation was observed in GC tissues compared to non-tumor tissues. Compared to the HC group, increased plasma circSLIT2 RNA accumulation was only observed in the GC group, but not in the IBS, GU, GT, and CD groups. Plasma circSLIT2 showed a positive correlation with circSLIT2 in GC tissues but not circSLIT2 in non-tumor tissues. Using increased plasma circSLIT2 as a biomarker, GC patients were effectively separated from other disease groups and the HC group. Survival curve analysis revealed that most patients who died during the 5‑year follow-up had high levels of circSLIT2 accumulation in GC tissues and plasma. CircSLIT2 in plasma and GC tissue was only closely associated with distant tumor metastases, but not other clinical factors.

CONCLUSION

Increased circSLIT2 accumulation may serve as a novel diagnostic and prognostic biomarker for GC.

Early stage gastric adenocarcinoma: clinical and molecular landscapes

Gastric adenocarcinoma, even when diagnosed at an early (localized) disease stage, poses a major health-care burden with cure rates that remain unsatisfactorily low, particularly in Western countries. This lack of progress reflects, among other aspects, the impracticality of early diagnosis, considerable variations in therapeutic approaches that is partly based on regional preferences, and the ingrained heterogeneity of gastric adenocarcinoma cells and their associated tumour microenvironment (TME). Clinical trials have long applied empirical interventions with the assumption that all early stage gastric adenocarcinomas are alike. Despite certain successes, the shortcomings of these approaches can potentially be overcome by targeting the specific molecular subsets of gastric adenocarcinomas identified by genomic and/or multi-omics analyses, including microsatellite instability-high, Epstein-Barr virus-induced, DNA damage repair-deficient, HER2-positive and PD-L1-high subtypes. Future approaches, including the availability of sophisticated vaccines, novel antibody technologies, agents targeting TME components (including fibroblasts, macrophages, cytokines or chemokines, and T cells) and novel immune checkpoint inhibitors, supported by improved tissue-based and blood-based diagnostic assays, seem promising. In this Review, we highlight current knowledge of the molecular and cellular biology of gastric adenocarcinomas, summarize the current approaches to clinical management of the disease, and consider the role of novel management and/or treatment strategies.

Robotic gastrectomy for gastric cancer: systematic review and future directions

BACKGROUND

Robotic gastrectomy (RG) using the da Vinci Surgical System for gastric cancer was approved for national medical insurance coverage in Japan in April 2018, and its number has been rapidly increasing since then.

AIM

We reviewed and compared current evidence on RG and conventional laparoscopic gastrectomy (LG) to identify the differences in surgical outcomes.

METHODS

Three independent reviewers systematically reviewed the data collected from a comprehensive literature search by an independent organization, focusing on the following nine endpoints: mortality, morbidity, operative time, estimated blood loss volume, length of postoperative hospital stay, long-term oncologic outcome, quality of life, learning curve, and cost.

RESULTS

Compared to LG, RG has lower intraoperative blood loss volume, shorter length of hospital stay, and shorter learning curve, but both procedures have similar mortality. Contrarily, its disadvantages include longer procedural time and higher costs. Although the morbidity rate and long-term outcomes are almost comparable, RG showed superior potentials. Currently, the outcomes of RG are considered comparable to or better than LG.

CONCLUSION

RG might be applicable to all gastric cancer patients who fulfill the indication of LG at institutions that meet specific criteria and are approved to claim the National Health Insurance costs for the use of the surgical robot in Japan.

The Health and Clinical Benefits of Medicinal Fungi

The human uses of mushrooms and cultured mycelium products for nutrition and medicine are detailed and supported by available human studies, which in many cases are clinical trials published in peer-reviewed journals. The major medically active immunomodulating compounds in the cell walls-chitin, beta-glucans, and glycoproteins, as well as lower weight molecules-nitrogen-containing compounds, phenolics, and terpenes-are discussed in relation to their current clinical uses. The nutritional content and foods derived from mushrooms, particularly related to their medical benefits, are discussed. High-quality major nutrients such as the high amounts of complete protein and prebiotic fibers found in edible and medicinal fungi and their products are presented. Mushrooms contain the highest amount of valuable medicinal fiber, while dried fruiting bodies of some fungi have up to 80% prebiotic fiber. These fibers are particularly complex and are not broken down in the upper gut, so they can diversify the microbiome and increase the most beneficial species, leading to better immune regulation and increasing normalizing levels of crucial neurotransmitters like serotonin and dopamine. Since the growth of medicinal mushroom products is expanding rapidly worldwide, attention is placed on reviewing important aspects of mushroom and mycelium cultivation and quality issues relating to adulteration, substitution, and purity and for maximizing medicinal potency. Common questions surrounding medicinal mushroom products in the marketplace, particularly the healing potential of fungal mycelium compared with fruiting bodies, extraction methods, and the use of fillers in products, are all explored, and many points are supported by the literature.

Clinical advantage of standardized robotic total gastrectomy for gastric cancer: a single-center retrospective cohort study using propensity-score matching analysis

BACKGROUND

Although recent studies have shown that robotic gastrectomy offers clinical advantages over laparoscopic gastrectomy in decreasing gastric cancer (GC) morbidity, studies focusing on robotic total gastrectomy (RTG) remain limited. The current study aimed to clarify whether the use of a robotic system could clinically improve short-term outcomes.

METHODS

Between January 2009 and June 2021, 371 patients diagnosed with both clinical and pathological Stage III or lower GC and underwent RTG or laparoscopic total gastrectomy (LTG) were enrolled in this study. The primary outcome was the incidence of intra-abdominal infectious complications over Clavien-Dindo classification grade IIIa. Demographic characteristics of those who underwent the RTG and LTG were matched using propensity-score matching (PSM), after which short-term outcomes were compared retrospectively.

RESULTS

After PSM, 100 patients were included in each group. The RTG group had a significantly shorter duration of hospitalization following surgery [RTG 13 (11-16) days vs. LTG 14 (11-19) days; p = 0.032] and a greater number of dissected LNs [RTG 48 (39-59) vs. LTG 43 (35-54) mL; p = 0.025], despite having a greater total operative time [RTG 511 (450-646) min vs. LTG 448 (387-549) min; p < 0.001]. In addition, the RTG group had significantly fewer total complications (3% vs. 13%, p = 0.019) and intra-abdominal infectious complications (1% vs. 9%; p = 0.023).

CONCLUSIONS

The current study showed that robotic surgery might improve short-term outcomes following minimally invasive radical total gastrectomy by reducing intra-abdominal infectious complications.

SFRP4 and CDX1 Are Predictive Genes for Extragastric Recurrence of Early Gastric Cancer after Curative Resection

Extragastric recurrence of early gastric cancer (EGC) after curative resection is rare, but prognosis has been poor in previous reports. Recently, single patient classifier (SPC) genes, such as secreted frizzled-related protein 4 (SFRP4) and caudal-type homeobox 1 (CDX1), were associated with prognosis and chemotherapy response in stage II–III gastric cancer. The aim of our study is, therefore, to elucidate predictive factors for extragastric recurrence of EGC after curative resection, including with the expression of SPC genes. We retrospectively reviewed electronic medical records of 1974 patients who underwent endoscopic or surgical curative resection for EGC. We analyzed clinicopathological characteristics to determine predictive factors for extragastric recurrence. Total RNA was extracted from formalin-fixed, paraffin-embedded (FFPE) tumor tissue and amplified by real-time reverse transcription polymerase chain reaction to evaluate expression of SPC genes. Overall incidences of extragastric recurrence were 0.9%. In multivariate analysis, submucosal invasion (odds ratio [OR] = 6.351, p = 0.032) and N3 staging (OR = 171.512, p = 0.012) were independent predictive factors for extragastric recurrence. Mean expression of SFRP4 in extragastric recurrence (−2.8 ± 1.3) was significantly higher than in the control group (−4.3 ± 1.6) (p = 0.047). Moreover, mean expression of CDX1 in extragastric recurrence (−4.6 ± 2.0) was significantly lower than in the control group (−2.4 ± 1.8) (p = 0.025). Submucosal invasion and metastasis of more than seven lymph nodes were independent predictive factors for extragastric recurrence. In addition, SFRP4 and CDX1 may be novel predictive markers for extragastric recurrence of EGC after curative resection.

LncRNA FEZF1-AS1 Promotes Multi-Drug Resistance of Gastric Cancer Cells via Upregulating ATG5

Long non-coding RNAs (lncRNAs) play important roles in human cancers including gastric cancer (GC). Dysregulation of lncRNAs is involved in a variety of pathological activities associated with gastric cancer progression and chemo-resistance. However, the role and molecular mechanisms of FEZF1-AS1 in chemoresistance of GC remain unknown. In this study, we aimed to determine the role of FEZF1-AS1 in chemoresistance of GC. The level of FEZF1-AS1 in GC tissues and GC cell lines was assessed by qRT-PCR. Our results showed that the expression of FEZF1-AS1 was higher in gastric cancer tissues than in adjacent normal tissues. Multivariate analysis identified that high level of FEZF1-AS1 is an independent predictor for poor overall survival. Increased FEZF1-AS1 expression promoted gastric cancer cell proliferation in vitro. Additionally, FEZF1-AS1 was upregulated in chemo-resistant GC tissues. The regulatory effect of FEZF1-AS1 on multi-drug resistance (MDR) in GC cells and the underlying mechanism was investigated. It was found that increased FEZF1-AS1 expression promoted chemo-resistance of GC cells. Molecular interactions were determined by RNA immunoprecipitation (RIP) and the results showed that FEZF1-AS1 regulated chemo-resistance of GC cells through modulating autophagy by directly targeting ATG5. The proliferation and autophagy of GC cells promoted by overexpression of LncFEZF1-AS1 was suppressed when ATG5 was knocked down. Moreover, knockdown of FEZF1-AS1 inhibited tumor growth and increased 5-FU sensitivity in GC cells in vivo. Taken together, this study revealed that the FEZF1-AS1/ATG5 axis regulates MDR of GC cells via modulating autophagy.

Improvement in the Mortality-to-Incidence Ratios for Gastric Cancer in Developed Countries With High Health Expenditures

The mortality-to-incidence ratio (MIR) is widely used to evaluate the efficacy of cancer management outcomes for individual countries. However, the association among health care expenditure, human development index (HDI), and changes in MIR over time (δMIR) remains unknown. We aimed to elucidate the significance between these indicators and gastric cancer outcomes in different countries. Among the regions, Asia had the highest number of new gastric cancer cases, gastric cancer-related deaths, age-standardized ratio of incidence, and mortality. Chile had the highest age-standardized ratio (ASR) for gastric cancer incidence and the highest ASR for mortality. Moreover, MIR was highest in Africa (0.91) and lowest in North America (0.43). Of note, MIR was negatively associated with HDI, current health expenditure (CHE) per capita, and CHE/GDP % and δMIR was positively associated with CHE/GDP % in countries with very high HDI. However, δMIR showed no significant associations with these indicators in the countries analyzed. In conclusion, increased HDI, CHE per capita, and CHE/GDP are associated with improved gastric cancer outcomes. In addition, the δMIR could be an indicator that can be used to evaluate the improvement in cancer management outcomes over time.

Lifestyles, genetics, and future perspectives on gastric cancer in east Asian populations

The prevalence of gastric cancer (GC) differs among regions worldwide, with the highest occurrence in east Asia. Thus, its etiology, with respect to ethnic background, environmental factors, and lifestyles, is also thought to differ essentially. In addition, etiology of GC is speculated to be changing due to the recent decrease in the Helicobacter pylori (H. pylori) infection in Japan. State-of-the-art somatic/germline cancer genomics has clarified the etiologies of gastric carcinogenesis. In this review article, we summarize past and present milestones in our understanding of GC achieved through genomic approaches, including a recent report that revealed higher-than-expected frequencies of GCs attributed to east Asian-specific germline variants in ALDH2 or CDH1 in combination with lifestyles. Based on this updated knowledge, we also discuss the possible impact of and high-risk approaches for GCs in the upcoming "H. pylori-negative era."

Taxane-based versus platinum-based chemotherapy in early recurrent gastric cancer after radical surgery with S-1 adjuvant chemotherapy: A multi-institutional retrospective analysis

AIM

This study aimed to compare the efficacy of taxane-based and platinum-based regimens in patients with early recurrent gastric cancer after radical surgery with S-1 adjuvant chemotherapy.

METHODS

The medical records of 118 patients from six institutes with early recurrent stage II/III gastric cancer, who developed recurrence during adjuvant S-1 or within 6 months after completion of adjuvant therapy between January 2006 and December 2017, were retrospectively analyzed. Patients treated with second line chemotherapy were enrolled and followed to the end of December 2019. The impact of two regimens, taxane-based (n = 46) versus platinum-based (n = 31), on treatment outcome were evaluated using multivariate analysis.

RESULTS

Median overall survival was 9.0 months and median progression-free survival was 4.1 months. No difference was observed in overall survival between taxane-based and platinum-based regimens (P = 0.64). Although not significant, the response rate of platinum-based regimens was better than that of taxane-based regimens (16% vs. 6.5%, P = 0.26). Multivariate analysis identified performance status (P = 0.040), multiorgan metastases (P = 0.029), and undifferentiated histological type (P = 0.018) as independent poor prognostic factors. In undifferentiated histological type, multiorgan metastases (P = 0.013) and taxane-based regimens (P = 0.018) were independent prognosis factors characterized by multivariate analysis. Conversion rate to third-line chemotherapy or more was 51% in undifferentiated histological type and 65% in differentiated histological type (P = 0.26).

CONCLUSION

Platinum-based regimens may be recommended for undifferentiated early recurrent gastric cancer after S-1 adjuvant chemotherapy.

MiR-450a-5p Inhibits Gastric Cancer Cell Proliferation, Migration, and Invasion and Promotes Apoptosis via Targeting CREB1 and Inhibiting AKT/GSK-3β Signaling Pathway

Gastric cancer seriously affects human health and research on gastric cancer is attracting more and more attentions. In recent years, molecular targets have become the research focus. Accumulating evidence indicates that miR-450a-5p plays a critical role in cancer progression. However, the biological role of miR-450a-5p in gastric carcinogenesis remains largely unknown. In this study, we explore the effects and mechanisms of miR-450a-5p on the development and progression of gastric cancer. We used gain-of-function approaches to investigate the role of miR-450a-5p on gastric cancer cell proliferation, migration, invasion, and apoptosis using biological and molecular techniques including real-time quantitative PCR (RT-qPCR), CCK-8, colony formation, flow cytometry, Western blot, wound healing, transwell chamber, dual luciferase reporter, and tumor xenograft mouse model. We found that gastric cancer cells have low expression of miR-450a-5p and overexpression of miR-450a-5p inhibited gastric cancer cell proliferation, migration and invasion, and induced apoptosis in vitro. Moreover, we demonstrated that ectopic expression of miR-450a-5p inhibited gastric cancer growth in vivo. At the molecular level, overexpression of miR-450a-5p significantly increased the expression of pro-apoptotic proteins, including caspase-3, caspase-9, and Bax, and inhibited the expression of anti-apoptotic protein Bcl-2. Luciferase reporter experiment suggested that camp response element binding protein 1 (CREB1) had a negative correlation with miR-450a-5p expression, and knockdown of CREB1 alleviated gastric cancer growth. Furthermore, we also found that miR-450a-5p inhibited the activation of AKT/GSK-3β signaling pathway to inhibit the progression of gastric cancer. Collectively, miR-450a-5p repressed gastric cancer cell proliferation, migration and invasion and induced apoptosis through targeting CREB1 by inhibiting AKT/GSK-3β signaling pathway. MiR-450a-5p could be a novel molecular target for the treatment of gastric cancer.

Clinical outcomes of proximal gastrectomy for gastric cancer: A comparison between the double-flap technique and jejunal interposition

Background

The optimal reconstruction method after proximal gastrectomy (PG) has been debatable. Recent reports have shown that the double-flap technique (DFT) provides good outcomes in terms of postoperative nutritional status and quality of life. However, no study has compared the clinical outcomes of the DFT with other reconstruction methods. Here, we evaluated and compared the clinical outcomes between the DFT and jejunal interposition (JI) after PG for gastric cancer.

Materials and methods

The medical records of 34 consecutive patients who had undergone PG for upper third gastric cancer between January 2011 and October 2016 were reviewed retrospectively. The main factors investigated were surgical outcomes, postoperative nutritional status, symptoms, and endoscopic findings 1 year after surgery.

Results

Thirty-four patients were enrolled (DFT, 14; JI, 20). The operation time was similar between the two techniques (228 and 246 minutes for DFT and JI, respectively, P = 0.377), as were the rates of anastomotic complications (7% and 0% for DFT and JI, respectively, P = 0.412). Body weight loss was significantly lower in the DFT group than in the JI group (-8.1% vs -16.1%, P = 0.001). Total protein and albumin levels were higher in the DFT group than in the JI group (0% vs -2.9%, P = 0.053, and -0.3% vs -6.1%, P = 0.077, respectively). One patient in the DFT group and no patients in the JI group experienced reflux esophagitis (≥ grade B) (P = 0.393). Anastomotic strictures were not observed as postoperative complications in either group.

Conclusions

Surgical outcomes revealed that the DFT was safe and feasible, similar to JI. In terms of controlling postoperative body weight loss, the DFT is a better reconstruction technique than JI after PG.

Neural signaling modulates metabolism of gastric cancer

Tumors comprise cancer cells and the associated stromal and immune/inflammatory cells, i.e., tumor microenvironment (TME). Here, we identify a metabolic signature of human and mouse model of gastric cancer and show that vagotomy in the mouse model reverses the metabolic reprogramming, reflected by metabolic switch from glutaminolysis to OXPHOS/glycolysis and normalization of the energy metabolism in cancer cells and TME. We next identify and validate SNAP25, mTOR, PDP1/α-KGDH, and glutaminolysis as drug targets and accordingly propose a therapeutic strategy to target the nerve-cancer metabolism. We demonstrate the efficacy of nerve-cancer metabolism therapy by intratumoral injection of BoNT-A (SNAP25 inhibitor) with systemic administration of RAD001 and CPI-613 but not cytotoxic drugs on overall survival in mice and show the feasibility in patients. These findings point to the importance of neural signaling in modulating the tumor metabolism and provide a rational basis for clinical translation of the potential strategy for gastric cancer.

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Metabolic reprogramming in gastric cancer cells and tumor microenvironment

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SNAP25, mTOR, PDP1/α-KGDH, and glutaminolysis as potential drug targets

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Combination of botulinum toxin type A, RAD001, and CPI-613 as a potential treatment

Comparison of Long-Term Efficacy in S-1 and Capecitabine With Oxaliplatin as Adjuvant Chemotherapy for Patients With Gastric Cancer After Curative Surgery: A Retrospective, Single-Center Observational Study

Purpose: Various adjuvant chemotherapies have been introduced for gastric cancer patients after gastrectomy with D2 lymph node dissection. Although the mainstream regimen of adjuvant chemotherapy in Korea includes S-1 monotherapy (TS-1) and capecitabine with oxaliplatin (XELOX), few studies have compared the long-term efficacies of these 2 regimens. Methods: Between January 2010 and June 2017, 2021 patients were diagnosed with gastric cancer and underwent curative resection with adjuvant chemotherapy at our institution. Of 1461 patients with stage IB-III gastric cancer, 825 received TS-1 and 636 received XELOX as adjuvant chemotherapy. We retrospectively reviewed their medical records and analyzed the postoperative 5-year overall survival (OS) and disease-free survival (DFS) of these 2 groups. Results: The patients in the XELOX group had more advanced stage of cancer than the TS-1 group (stages III and II: 56.6% and 43.1%, respectively, in XELOX and 35.3% and 57.0% in TS-1; P < .001). The DFS did not differ significantly between the 2 study groups at any pathologic stage. The OS differed significantly only at pathologic stages IIA (P = .024) and IIB (P = .015). In a multivariate analysis of stage II patients, type of regimen was an independent prognostic factor of OS (XELOX vs TS-1; hazard ratio: 0.47, 95% confidence interval: 0.25-0.89, P = .021). Conclusion: There were similar long-term efficacies between these 2 regimens in advanced gastric cancer patients who underwent curative surgery. However, the XELOX regimen might be favorable for OS of stage II patients.

Recurrent gastric cancer sustaining a partial response after the nivolumab discontinuation because of immune-related adverse events: a case report

Background

The prognosis of patients with recurrent gastric cancer is poor despite chemotherapy being clinically recommended as the first therapeutic strategy. Recent clinical trials have established the clinical utility of nivolumab in the third-line treatment of such patients. Immune-related adverse events (irAE) have been focused as a promising predictor for tumor response to nivolumab. This report aims to present a long-term survivor of recurrent gastric cancer who was followed up without any treatments after the nivolumab discontinuation because of irAE.

Case presentation

A 65-year-old male with stage III gastric cancer (cT4aN1M0) underwent surgery after neoadjuvant chemotherapy. Owing to the final pathological stage IIIB (ypT4bN1M0), the patient received adjuvant chemotherapy. Nevertheless, during adjuvant chemotherapy 1-year post-surgery, computed tomography (CT) revealed lymph node swelling in station no. 9. Thus, upon diagnosis with lymph node recurrence, the patient was treated with two courses of capecitabine + oxaliplatin and three courses of ramucirumab + paclitaxel as the first- and second-line regimens, respectively. Based on these regimens, the patient had a progressive disease to chemotherapy. Consequently, we administered nivolumab as the third-line regimen. After four courses of nivolumab, CT revealed a significant shrinkage of the metastatic lymph node, with a 45.6% reduction. We confirmed a partial response during 11 courses of nivolumab. Since the occurrence of grade 4 diabetes mellitus after 12 courses of nivolumab, the patient was followed up without any treatment after the nivolumab discontinuation. Currently, the patient remains a partial response for 15 months, since the nivolumab discontinuation and is alive for 31 months after disease recurrence.

Conclusions

Acute irAE during nivolumab chemotherapy could be one of the crucial clinical factors to predict tumor suppression in patients with advanced gastric cancer.

Postprandial Changes in Gastrointestinal Hormones and Hemodynamics after Gastrectomy in Terms of Early Dumping Syndrome

Purpose

This study aimed to examine the early postprandial changes in gastrointestinal (GI) hormones and hemodynamics in terms of early dumping syndrome after gastrectomy for gastric cancer.

Materials and Methods

Forty patients who underwent gastrectomy for gastric cancer and 18 controls without previous abdominal surgery were enrolled. Before and 20 minutes after liquid meal ingestion, blood glucose, glucagon-like peptide-1 (GLP-1), and GLP-2 concentrations and superior mesenteric artery (SMA) and renal blood flow were measured. The patients' heart rates were recorded at 5-minute intervals. All subjects were examined for dumping syndrome using a questionnaire based on Sigstad's clinical diagnostic index.

Results

The postprandial increases in blood glucose, GLP-1, and GLP-2 levels as well as SMA blood flow and heart rate were greater in patients who underwent gastrectomy than in controls (all P<0.010). Patients who underwent gastrectomy showed a significantly decreased renal blood flow (P<0.001). Among patients who underwent gastrectomy, distal gastrectomy was a significant clinical factor associated with a lower risk of early dumping syndrome than total gastrectomy (hazard ratio, 0.092; 95% confidence interval, 0.013–0.649; P=0.017). Patients who underwent total gastrectomy showed a greater postprandial increase in blood glucose (P<0.001), GLP-1 (P=0.030), and GLP-2 (P=0.002) levels as well as and heart rate (P=0.013) compared to those who underwent distal gastrectomy.

Conclusions

Early postprandial changes in GI hormones and hemodynamics were greater in patients who underwent gastrectomy than in controls, especially after total gastrectomy, suggesting that these changes play a crucial role in the pathophysiology of early dumping syndrome.

Present status and perspective of chemotherapy for patients with unresectable advanced or metastatic gastric cancer in Japan

Patients with unresectable advanced or recurrent gastric cancer have a poor prognosis with overall survival times increasing by only a few months after anti-cancer drug therapy in the last four decades. The survival times from previous clinical trials for untreated metastatic gastric cancer in Japan are generally better than those reported from trials in European and North or South American countries. Therefore, the proportion of Japanese patients enrolled in recent global trials of novel anti-cancer drugs should be increased in order to identify drugs that specifically prolong the survival of such patients. S-1 plus oxaliplatin (SOX) therapy is the most commonly used standard first-line treatment for advanced gastric cancer in Japan. SOX induces mild nausea and vomiting, even in elderly patients, that can be treated by maintaining oral intake with adequate anti-emetic treatment usually given in an outpatient clinic. Neutropenia, nausea, and vomiting in SOX therapy were more frequently observed in female patients compared with males. Intensive toxic chemotherapy such as triplet therapy never prolonged overall survival or maintained a favorable quality of life. The current strategies used against metastatic gastric cancer need to be modified in regard to innovative treatments with current drugs, keeping in mind each categorized treatment population. In a real world of a diverse society even if the same treatment is performed, the outcome of the individual patient is different. It is important for each society to implement established treatment, knowing that the evidence from global trials aimed at drug approval does not necessarily show external validity.

Gastric carcinoma: Insights into risk factors, methods of diagnosis, possible lines of management, and the role of primary care

Gastric carcinoma represents the second most common type of malignancy that contributes to cancer-related mortality worldwide. However, the geographic incidence of gastric carcinoma had changed over the last few decades, possibly due to increased hygiene, increased awareness of the importance of healthy nutrition, and increased rates of eradication of Helicobacter pylori infection. Gastric carcinoma consists of two pathological variants, intestinal and diffuse. Early cases of gastric carcinoma may be asymptomatic. However, advanced cases may present with significant weight loss, dysphagia, abdominal pain, vomiting, and even severe upper gastrointestinal bleeding. Patients at high risk of developing gastric carcinoma should be adequately screened at primary healthcare centers for early detection and effective management. Lines of treatment vary according to the stage of the disease but surgical resection of the tumor with regional lymphadenectomy remains the gold standard of therapy. This review sheds light on gastric carcinoma given the recent trends regarding its prevalence, risk factors, types, clinical picture, methods of diagnosis, possible lines of management, and the role of primary care.

Non-robotic minimally invasive gastrectomy as an independent risk factor for postoperative intra-abdominal infectious complications: A single-center, retrospective and propensity score-matched analysis

BACKGROUND

Minimally invasive surgery for gastric cancer (GC) has gained widespread use as a safe curative procedure especially for early GC.

AIM

To determine risk factors for postoperative complications after minimally invasive gastrectomy for GC.

METHODS

Between January 2009 and June 2019, 1716 consecutive patients were referred to our division for primary GC. Among them, 1401 patients who were diagnosed with both clinical and pathological Stage III or lower GC and underwent robotic gastrectomy (RG) or laparoscopic gastrectomy (LG) were enrolled. Retrospective chart review and multivariate analysis were performed for identifying risk factors for postoperative morbidity.

RESULTS

Morbidity following minimally invasive gastrectomy was observed in 7.5% of the patients. Multivariate analyses demonstrated that non-robotic minimally invasive surgery, male gender, and an operative time of ≥ 360 min were significant independent risk factors for morbidity. Therefore, morbidity was compared between RG and LG. Accordingly, propensity-matched cohort analysis revealed that the RG group had significantly fewer intra-abdominal infectious complications than the LG group (2.5% vs 5.9%, respectively; P = 0.038), while no significant differences were noted for other local or systemic complications. Multivariate analyses of the propensity-matched cohort revealed that non-robotic minimally invasive surgery [odds ratio = 2.463 (1.070–5.682); P = 0.034] was a significant independent risk factor for intra-abdominal infectious complications.

CONCLUSION

The findings showed that robotic surgery might improve short-term outcomes following minimally invasive radical gastrectomy by reducing intra-abdominal infectious complications.